[BUGFIX] Don't render broken extension icons in language packs updater

The icon path of an extension is only returned if the icon can be found.
This prevents the JavaScript from rendering a broken extension icon.

Resolves: #91038
Releases: master, 9.5
Change-Id: Ic0a4fb874215408c1781b3acb29e9ec4769150fd
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/64176


Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Oliver Bartsch <bo@cedev.de>
Tested-by: Georg Ringer <georg.ringer@gmail.com>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Reviewed-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>